title: Cortical inhibition reduces information redundancy at presentation of communication sounds in the primary auditory cortex.
abstract: In all sensory modalities, intracortical inhibition shapes the functional properties of cortical neurons but also influences the responses to natural stimuli. Studies performed in various species have revealed that auditory cortex neurons respond to conspecific vocalizations by temporal spike patterns displaying a high trial-to-trial reliability, which might result from precise timing between excitation and inhibition. Studying the guinea pig auditory cortex, we show that partial blockage of GABAA receptors by gabazine (GBZ) application (10 μm, a concentration that promotes expansion of cortical receptive fields) increased the evoked firing rate and the spike-timing reliability during presentation of communication sounds (conspecific and heterospecific vocalizations), whereas GABAB receptor antagonists [10 μm saclofen; 10-50 μm CGP55845 (p-3-aminopropyl-p-diethoxymethyl phosphoric acid)] had nonsignificant effects. Computing mutual information (MI) from the responses to vocalizations using either the evoked firing rate or the temporal spike patterns revealed that GBZ application increased the MI derived from the activity of single cortical site but did not change the MI derived from population activity. In addition, quantification of information redundancy showed that GBZ significantly increased redundancy at the population level. This result suggests that a potential role of intracortical inhibition is to reduce information redundancy during the processing of natural stimuli.
authors.affiliation: Centre de Neuroscience de Paris-Sud, UMR CNRS 8195 and University Paris-Sud, 91405 Orsay cedex, France.
authors.forename: Quentin
authors.initials: Q
authors.lastname: Gaucher
authors.forename: Chloé
authors.initials: C
authors.lastname: Huetz
authors.forename: Boris
authors.initials: B
authors.lastname: Gourévitch
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Edeline
mesh_terms: D000465:Algorithms; D000819:Animal Communication; D000818:Animals; D001303:Auditory Cortex / Q000166:cytology / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology; D001418:Baclofen / Q000031:analogs & derivatives / Q000494:pharmacology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D004192:Discrimination, Psychological / Q000502:physiology; D055724:Electrophysiological Phenomena; D005110:Extracellular Space; D005260:Female; D018756:GABA Antagonists / Q000494:pharmacology; D006168:Guinea Pigs; D008297:Male; D008845:Microinjections; D009474:Neurons / Q000502:physiology; D018408:Patch-Clamp Techniques; D010721:Phosphinic Acids / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D011724:Pyridazines / Q000494:pharmacology; D011963:Receptors, GABA-A / Q000187:drug effects; D018080:Receptors, GABA-B / Q000187:drug effects; D014828:Vocalization, Animal / Q000502:physiology*
chemical_list: D018756:GABA Antagonists; D010721:Phosphinic Acids; D011412:Propanolamines; D011724:Pyridazines; D011963:Receptors, GABA-A; D018080:Receptors, GABA-B; C085075:CGP 55845A; C049853:gabazine; D001418:Baclofen; C080629:saclofen